This group of spreadsheets (sailings.xls, waypoints.xls, composite.xls) can assist you in planning your trip from the point of Departure to Destination. The example preset in these spreadsheets pertains to a trip from San Francisco (USA) to Yokohama (Japan). This choice is inspired by Figure 2404 in Bowditch (p. 347).

In spreadsheet sailings.xls you enter the coordinates of the Departure and Destination points in row 2. The spreadsheet calculates the distances and courses from Departure to Destination along the resulting great circle (columns B, C) and rhumb line (columns E, F). The results are displayed both assuming a perfectly spherical (row 6) as well as a flattened (row 7) Earth model. The initial great-circle course in the yellow cell C6 is displayed with (otherwise unrealistic) three decimal places in order to minimize numerical round-off errors when that value is subsequently copied into the D2 input cell of the spreadsheet waypoints.xls. Finally, row 11 displays the coordinates of the great-circle vertex on the path from Departure toward Destination.

Summary for spreadsheet sailings.xls:

Input cells: B2, C2, E2, F2

Output cells: B6, C6, E6, F6, B7, C7, E7, F7, row 11

The spreadsheet waypoints.xls takes the coordinates of the Departure point (cells B2, C2) and (in cell D2) the initial course (e.g. from cell C6 in sailings.xls). Row 7 displays the great-circle vertex. Starting in row 11 you can use column A to specify the longitude of each waypoint along the great circle. The spreadsheet then calculates the corresponding latitude (columns C, D, E) and the (flattened Earth model) rhumb-line distance (column F) and the constant course (column G) from the previous waypoint. The total length of this path is shown in cell F2.

Summary for spreadsheet waypoints.xls:

Input cells: B2, C2, D2, column A starting in row 11

Output cells: F2, row 7, columns C, D, E, F, G starting in row 11